This invention relates to a sleeve carton erecting, loading and sealing machine for packaging a plurality of articles in such cartons and, more particularly, to end panel folding and sealing apparatus which folds the end panels of the cartons against the carton dust flaps and presses the end panels and dust flaps together to seal the carton and complete the packaging operation.
Sleeve carton machines which erect folded sleeve carton blanks, load articles to be packed into the sleeve thus formed, and seal the dust flaps and end panels of the cartons together to form a package are used extensively in the beer and soft drink industries to package beverage cans in twelve packs and the like. These sleeve carton machines normally employ static folding bars for folding the end panels of the cartons against the carton dust flaps and pressing them together while the glue applied between the end panels and dust flaps sets and the cartons are sealed.
The sleeve carton machines which employ the static folding bars operate to carton packaging rates approaching 150 cartons per minute. However, with increased demands for beer and soft drink beverages the industry has a continuing need to increase the packaging rates of its machines so that each machine can package more articles. The static folding bars of the prior art machines present a problem. The static folding bars exert a drag on the end panels as the end panels are folded and pressed against the dust flaps by the static bars. This causes the cartons to be formed out of square and the end panels do not line up properly with the dust flaps and the sides of the cartons. This presents an aesthetic problem. The misalignment of the carton panels and flaps gives the carton a haphazard or poorly formed appearance to the consumer. In addition, corners of the end panels projecting beyond the side walls of the cartons can catch on other packages or objects. This interferes with the handling and stacking of such packages and can result in the tearing of the end panels.
The carton erecting, loading and sealing machine of the present invention is provided with a unique end panel folding and carton sealing assembly. The present invention eliminates the static folding bars and any need for an auxiliary end panel folding assembly for folding the end panels on machine shutdowns.
The end panel folding and carton sealing assembly of the present invention includes a pair of upper folding plates and a pair of lower folding plates. The plates are located on either side of and adjacent to the carton conveyor. Each folding plate is mounted through rotatable mountings to a pair of cranks which move the folding plates through a cycle wherein the plates fold the end panels against the dust flaps and press the end panels against the dust flaps while glue applied between the end panels and dust flaps sets. The motion imparted to the folding plates by the cranks during this folding and sealing cycle also moves the plates in a downstream direction while the plates are in contact with the end panels. This greatly reduces or eliminates the drag exerted on the end panels and has permitted an increase in operating speeds of such machines to 200 packages per minute without misalignment of the end panels.
Another advantage of the present invention is the elimination of any need for an auxiliary end panel folding mechanism. On normal shutdowns the drives of the folding plates are controlled to stop the folding plates at substantially the midpoints of their folding and sealing cycles thereby assuring that any carton in the folding and sealing station is sealed.